This case might be related to Huntington Disease that is genetic and the dementia onsets at the age around 50s. And this is able to detectable by blood DNA test. Huntington Disease onset age is earlier than Alzheimer Dis. at 70 yo. By his wife subjective complaints, I am pretty sure/ confirm this diagnosis and I know the final result. Feel sad for the case and I need to cherish that I am still in good condition